Leverhulme Research Centre for Forensic Science, School of Science and Engineering, University of Dundee, Dundee, DD1 4HN, UK.
Leverhulme Research Centre for Forensic Science, School of Science and Engineering, University of Dundee, Dundee, DD1 4HN, UK.
Anal Chim Acta. 2023 Nov 15;1281:341926. doi: 10.1016/j.aca.2023.341926. Epub 2023 Oct 17.
The outbreak of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) which was first reported in early January 2020, continues to devastate the worlds public health system. Herein, we report on the development of a novel metal-enhanced fluorescence (MEF) and electrochemical biosensor for SARS-CoV-2 spike (S) protein. To develop the MEF biosensor, SiO-coated Si-doped ZnSeS quantum dots (QDs) were newly synthesized and conjugated to an aptamer-molecular beacon (Apta-MB) probe. Thereafter, cationic AuNPs, used as a localised surface plasmon resonance (LSPR) signal amplifier, were self-assembled on the QDs-Apta-MB conjugate to form a QDs-Apta-MB-AuNP probe. To develop the electrochemical biosensor, the QDs-Apta-MB assay was carried out on a carbon nanofiber-modified screen-printed carbon electrode. Cyclic voltammetry (CV), differential pulse voltammetry (DPV) and electrochemical impedance spectroscopy (EIS) were used to characterize the electrode surface whilst spectrophotometric, spectroscopic, fluorescence polarization and electron microscopic techniques were used to characterize the materials. Under optimal experimental conditions, the QDs binding to the Apta-MB, quenched the QDs' fluorescence and with SARS-CoV-2 S protein binding to the Apta-MB, LSPR signal from cationic AuNPs of different sizes and shapes were used to tune the fluorescence signal to obtain enhanced sensitivity. On the other hand, using [Fe(CN)]/K/ buffered with NaAc-KAc-TrizmaAc-KSCN-Borax as the electrolyte solution, anodic peaks of the QDs from the CV and DPV plots were unravelled. Electrochemical detection of SARS-CoV-2 S protein was accomplished by a systematic increase in the QDs anodic peak current generated from the DPV plots. The limits of detection obtained for the SARS-CoV-2 S protein were 8.9 fg/mL for the QDs-Apta-MB-AuNP MEF probe and ∼0.5 pg/mL for the QDs-Apta-MB electrochemical probe. Detection of SARS-CoV-2 S protein in saliva was demonstrated using the QDs-Apta-MB-AuNP MEF probe.
严重急性呼吸综合征冠状病毒 2（SARS-CoV-2）的爆发于 2020 年初首次报告，继续摧毁着世界公共卫生系统。在此，我们报告了一种新型金属增强荧光（MEF）和电化学生物传感器用于检测 SARS-CoV-2 刺突（S）蛋白。为了开发 MEF 生物传感器，新合成了涂覆有二氧化硅的掺锌硒化锌量子点（QDs）并与适体-分子信标（Apta-MB）探针偶联。此后，阳离子金纳米颗粒（AuNPs）用作局域表面等离子体共振（LSPR）信号放大器，自组装在 QDs-Apta-MB 偶联物上形成 QDs-Apta-MB-AuNP 探针。为了开发电化学生物传感器，在经过碳纳米纤维修饰的丝网印刷碳电极上进行了 QDs-Apta-MB 测定。循环伏安法（CV）、差分脉冲伏安法（DPV）和电化学阻抗谱（EIS）用于对电极表面进行表征，同时使用分光光度法、光谱法、荧光偏振和电子显微镜技术对材料进行了表征。在最佳实验条件下，与 Apta-MB 结合的 QDs 猝灭了 QDs 的荧光，并且随着 SARS-CoV-2 S 蛋白与 Apta-MB 的结合，使用不同大小和形状的阳离子 AuNPs 的 LSPR 信号来调整荧光信号以获得增强的灵敏度。另一方面，使用 [Fe(CN)6]3-/4-作为电解质溶液，以 NaAc-KAc-TrizmaAc-KSCN-Borax 缓冲，从 CV 和 DPV 图谱中解开了 QDs 的阳极峰。通过从 DPV 图谱中产生的 QDs 阳极峰电流的系统增加来完成对 SARS-CoV-2 S 蛋白的电化学生物检测。对于 QDs-Apta-MB-AuNP MEF 探针，获得了 SARS-CoV-2 S 蛋白的检测限为 8.9 fg/mL，对于 QDs-Apta-MB 电化学生物探针，检测限为 ∼0.5 pg/mL。使用 QDs-Apta-MB-AuNP MEF 探针在唾液中检测到 SARS-CoV-2 S 蛋白。
